Energy costs: How cotton gins can save money

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Continually rising energy costs for cotton gins make it all the more important to achieve optimum levels of operating efficiency, says Tommy Valco, USDA/ARS technology transfer coordinator at Stoneville, Miss.

Two operating practices can help ginners increase efficiency and save money on energy costs, based on research at the USDA/Agricultural Research Service’s Cotton Ginning Laboratory at Stoneville, Miss.

“Energy use has been an important concern at all our research labs, and all ginners are aware of continually rising energy costs,” says Tommy Valco, USDA/ARS technology transfer coordinator at Stoneville, Miss., who discussed the studies at the summer meeting of the Southern Cotton Ginners Association at Biloxi, Miss.

An energy monitoring project, involving on-site investigative studies at commercial gins, was designed to determine what kind of energy is being used, how, when, and where, for the different gin components, he says.

“We went into the gins and hooked up ammeters and data loggers to measure energy used, as well as power factors, for each operation. This helped to identify what was going on, how the efficiently system was working.

“Our findings very clearly show that the number of kilowatt hours per bale is reduced significantly as the number of bales per hour increase. One gin we studied averaged a very low 26 kWh per bale, which was amazing — most gins never hit that kind of number. But we do have some gins operating at 30 kWh, which is a very good number. On average, most gins are in the 40 to 45 kWh range.”

A key finding from the studies, Valco says: “You need to keep the gin as fully loaded as possible. Too many times, we find gins running at only 70 percent to 80 percent of capacity, which is just burning energy needlessly. If we can keep them running at 85 percent to 90 percent of capacity, they’re operating much more efficiently.”

A survey of Mid-South gins was conducted a few years ago to evaluate feeding rates for the seed cotton cleaning system, he says.

“Even though ginning equipment manufacturers all have good equipment, there wasn’t a lot of data available about loading rates. We wanted to be able to provide information that will be helpful to ginners, as well as to manufacturers in improving equipment design in order to operate as efficiently as possible.

“The Cotton Ginners Handbook shows a maximum feeding rate of about 2.5 bales of hour per foot of width,” Valco says, “but many gins are running much higher than that. Our survey showed some exceeded 4 or 4.5 bales per hour per foot.

“This stimulated a new research project. After upgrading our micro-gin at the Ginning Laboratory to increase capacity, we were able to increase the feeding rate to 3 to 4 bales per hour per foot of width, and in some situations as much as 6 bales per hour. This allowed us to update our data on cylinder cleaning settings, spacing, speed, etc.”

The study identified such factors as how much fiber is lost as seed cotton cleaning rate increases, the quality of the ginned cotton — “which is critical to the process” — and the variability of cleaning from one year to another.

“We need to keep gin stands fully loaded, insure that cotton enters the gin at the desirable moisture content, and minimize air usage as much as possible,” Valco says.

How gin shutdowns are handled can also affect operational efficiency and energy use, he notes.

“The data we’ve collected show if the idling time will be 12 minutes or greater, it’s better to shut down the gin, then start it back up after the problem is solved.”